Toward an Optimal Lighting Range: Insights into Visual Comfort and Occupant Well-being in Offices

Visual comfort plays a crucial role in the effectiveness and well-being of office occupants, as lighting directly affects task performance. Consequently, the presence, quality, and intensity of light are important considerations in both architectural design and operational planning. This study examines occupant satisfaction with lighting conditions in office workspaces using a three-pronged methodological approach. First, subjective data were collected through interviews with office occupants to assess perceived visual comfort. Second, an objective evaluation was conducted via a questionnaire distributed using random sampling techniques, wherein participants rated their satisfaction with lighting levels on a scale from 20% to 100%. Third, the collected responses were analysed using an independent samples t-test to verify the mean satisfaction range. The findings support the development of a visual comfort rating scale for office buildings in the Indian context. Surveys were conducted across 15 office buildings, encompassing 513 participants under three distinct lighting conditions. Results indicated that 95% of respondents reported satisfaction within an illuminance range of 150 to 300 lux (±50 lux). However, the study also found that many office environments do not meet this comfort standard. A common issue is the occurrence of glare due to over-illumination from fully glazed facades, which adversely affects both energy efficiency and occupant well-being.